Bottom bar not responding

Hi dear Chuwi and forum members.

I would like your help to the following problem with my Hi9Air.

Since yesterday afternoon, I have the following problem:
The bottom bar (the one that reside soft keys - I do not know if this bar has specific name), is not responding. It’s not only soft keys, but whole bar:from left to right. I think it is a specific bar, because, if someone with this tablet is on e.g. a page or application that can be seen the rectangle of this small bar. It must be a specific bottom bar. So, this small bottom bar, has stopped responding since yesterday.

I can see that, the full bar cannot work, and not only softkeys, also, from the following:

If I run YouTube, run a video on full screen, display video’s time bar, I cannot work on video’s time bar with my finger to go video back/forward. And this is because, on full screen, videos’ time bar is in the area of the not responding bottom bar.

Also, if I run YouTube videos on full screen, if I display on the bottom right corner the small icon of YouTube that turns video from full screen to Window, it also does not work, because this icon is on not responding area.

And from now on, other applications, that need this area, I won’t be able to work on them.

This not responding problem happened just suddenly. I was working on tablet yesterday afternoon, everything was working just perfect. I left the tablet, to go work on my pc, and after 2 hours, I went back to the tablet, and that’s it. Since then, the bar is not responding.

Tablet is not crashed anywhere.
No update is made on any application.

So, please, could you help me with this problem?

For any other information that you would like to ask me to help for the solution, I am here.

Thank you for your reading and time,
John